Your flight to Morocco will leave from T4S, as T4 is reserved to the Schengen zone flights. Most likely (but not absolutely certain), your flight from London will also arrive at T4S (same reason), although some IB flights arrive at T4. Do not use the lounges in T4, which are geared to medium haul, i.e mediocre catering, less space, more crowds. the lounge in T4S closest to your departure gate is the best one, plenty of space, sandwiches, excellent wine bar etc...

By the way, if you are a cigar smoker, the shop in Madrid T4 is the best in Europe, also the cheapest, far better than in T4S which only has overpriced Havanas, no Dominicans nor others. For those who insist on Havanas, the shop in T4 has them at a price lower than T4S by at least 15 %. Not having Dominicans in T4S is a drag on US bound passengers who cannot bring in Cuban cigars. (Aena, take note...)